1. Field of the Invention
The present application generally relates to electronic communications, and, more particularly, to communications systems, methods and devices having intelligent speech recognition and processing.
2. Description of the Related Art
Background noise, room reverberation, and signal distortions in modern communication systems (e.g., cellular telephones) destroy many important speech cues resulting in an impoverished speech signal. Speech, however, contains many redundant cues and it is possible for a person with normal hearing to use these redundancies to compensate for the loss of speech cues for most of the noisy, reverberant or other forms of distorted speech encountered in everyday life. This is not a fortuitous accident. Legislation, public pressure, and related factors have resulted in reduced background noise in the workplace, public places, schools, etc. so that speech communication is relatively efficient most of the time for people with normal hearing. A person with a hearing loss, however, has to deal with two forms of impoverished speech, the loss of speech cues resulting from reduced neural processing of signals in the impaired auditory system, and the additional loss of speech cues in distorted speech. Whereas many people with hearing loss are able to understand undistorted speech in quiet using redundant speech cues to compensate for the loss of speech cues resulting from deficient neural processing in the impaired auditory system, distorted speech signals are substantially more difficult to understand. Amplification is useful for improving the intelligibility of undistorted speech in quiet in that it increases the audibility of many of the useful redundant cues in the impoverished speech signal. If, however, the amplified speech signal is distorted (e.g., background noise is amplified as well as the speech signal), there are substantially fewer remaining redundant speech cues to compensate for the combined loss of speech cues resulting from deficient neural processing in the impaired auditory system and the loss of speech cues in distorted speech signals. Seniors with a hearing loss also have age-related deficits in neural and cognitive processing, particularly with respect to processing rapid temporal changes. As a consequence, these seniors have substantially greater difficulty than young normal hearing adults understanding speech with the kinds of distortions commonly encountered in everyday life. Conventional amplification is of little benefit in improving the intelligibility of distorted speech, particularly speech with rapid temporal distortions.
The field of automatic speech recognition has made substantial progress in recent years. Machine recognition of speech is now a practical reality although not yet as efficient as human speech recognition. However, algorithms using the technology of automatic speech recognition have been developed to improve the intelligibility and quality of impoverished speech. The signal processing algorithms implemented in hearing aids, however, process the acoustic signal only. In contrast, automatic speech recognition algorithms use all of the information in the speech signal, which may include optic, phonetic, linguistic and/or statistical information. The many redundancies in the speech signal that enable understanding of impoverished speech are conveyed by both the acoustic and optic components of speech in face-to-face communication, particularly under challenging listening conditions.